Private Lives of Island View Beach`s Western Black Widows

Transcription

Private Lives of Island View Beach`s Western Black Widows
Volunteers
Spring Newsletter 2014 | Capital Regional District
Feature:
Western Black Widows
VIP Profile:
Claire Buchanan
In Parks
Staff Profile:
George Golmer
Volunteer &
Park Updates
Private Lives of
Island View
Beach’s Western
Black Widows
V
By Catherine Scott
isitors to Island View
Beach may be surprised to
learn that western black
widows are the predominant
web-building spiders in the area.
Most people will never see them, as they
are nocturnal, shy, and unaggressive.
During the day they stay hidden under
logs, but after dark they come out onto
their webs and wait for prey to blunder
into their silken traps.
A female western black widow hangs from her web during the night, waiting for her next
meal, or a courting male. The capture web extends from a silken retreat under the driftwood,
where she shelters during the day. Belying their name, females of this species rarely consume
males, who are much smaller than their typical prey. Photo Sean McCann
Regional Parks
490 Atkins Avenue
Victoria, BC V9B 2Z8
T: 250.478.3344
parksvolunteer@crd.bc.ca
www.crd.bc.ca/parks
Male western black widows are variable in
colour and much smaller than the familiar
black females. Once they mature, males
abandon their webs to wander the dunes
in search of mates. My research examines
the sexual communication system of these
beautiful, mysterious spiders.
Continued page 2
Top: The diminutive, colourful male western black widow spends his adult life wandering the dunes, searching for females. This male has climbed up
onto the vegetation, perhaps to get a ‘whiff’ of a female’s web on the wind. Right: This cage, with an intact female’s web inside, was surrounded with
sticky strips to capture males that were attracted to the female’s silk pheromones. At least 15 spiders can be seen trapped outside this cage.
Female black widows build large three-dimensional
cobwebs, which not only ensnare prey, but are also used for
communication. Pheromones (chemical signalling molecules)
on the silk allow males to ‘sniff out’ potential mates. These
chemicals can tell the male whether the female is well fed
or starving (indicating the risk of cannibalism), and if she
has previously mated. This information may help him decide
whether to enter a web and begin his courtship display, or
move on in search of a more receptive female.
does in fact decrease the attractiveness of a female’s web.
It’s not yet clear if this is a result of suppressing the female’s
signals, the addition of male silk pheromones, or both, but we
now understand more about the function of this behaviour.
With web-reduction, the male manipulates the female’s
attractive pheromone signals, reducing the chances of other
males finding her web and competing for her affections.
Next time you’re out at Island View Beach, take a closer look
at the woody habitat that is home to a whole host of species
including the black widows. You might spot a tangled web
extending from under a log onto the sand or nearby vegetation.
This sophisticated structure acts as both an effective trap for
prey and an aromatic advertisement for mates. Below the
driftwood, elegant spiders play a deadly but vital role in the
diverse coastal dune ecosystem.
‘Web-reduction’ is a curious part of the male’s courtship display,
which includes sending vibratory signals through the web to
the female. Soon after a male enters a female’s web he often
begins dismantling it, cutting and bundling up large sections,
then wrapping them up with his own silk. We wanted to find
out if web-reduction behaviour decreases the attractiveness of
a female’s web. The shrunken surface area of the web could
minimize the release of attractive pheromones, or the added
male’s silk might carry its own pheromones that are repellent
to other males.
Catherine Scott is a MSc student at
Simon Fraser University. She and
her colleagues are researching
the western black widow at Island
View Beach and on the traditional
lands of the Tsawout First Nation
with their generous permission
and support. Photos courtesy Sean
McCann. Find out more about the
research on Catherine’s blog at
spiderbytes.org.
To study the function of web-reduction, we ran an experiment
on the beach. We set out cages containing both intact and malereduced females’ webs and surrounded them with sticky traps
to capture males that were attracted to the scent of the silk.
In a single night we captured more than 200 mate-searching
males outside the cages. We caught far fewer spiders with
reduced webs than intact webs, indicating that web-reduction
CRD Volunteers in Parks Spring 2014 Newsletter
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C
VIP Profile
laire Buchanan is a Park Naturalist at Witty’s
Lagoon Regional Park in Metchosin. She
has volunteered with the CRD since 2012.
What do you enjoy most about volunteering?
My favorite part of volunteering with Regional Parks is seeing
the excitement on visitors’ faces when they come into the
nature house after seeing something really neat in the park. I
love hearing their stories. I think it’s important to have places,
like the nature house, where people can share their interest in
the natural environment.
What is your favourite volunteer experience or memory?
My favorite memory of volunteering happened on a rainy day.
The nature house had been very quiet all day until a mother
and her daughter came in. They were really interested in the
natural environment of the park because they were new to
the area, and wanted to learn more about their new home.
We spent an hour going through the showcase and all the
drawers in the nature house examining and learning about all
the different species you could find in Witty’s Lagoon. It was a
great experience to learn and share together.
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Staff Profile
eorge Golmer is a Parks Operations
Supervisor for Regional Trails and the
Gulf Islands.
Where have you worked previously?
Starting at 15 years old I was employed as a lifeguard at Elk/
Beaver Lake Park for (then) Saanich Parks. I did this for several
summers while going to school. I also volunteered with Saanich
conducting Colquitz Creek cleanups and did trails and grounds
maintenance at both Elk/Beaver and Cedar Hill Golf Course.
In 1976 I started my career with CRD Parks as their Head
Lifeguard and have since worked in every park, in almost every
capacity. While working for CRD Parks I have experienced more
opportunities and challenges than I could ever have imagined.
What is your favourite park?
Thetis Lake because of its natural beauty, proximity to the city
and size. This park is amazing, large enough that you can get
lost and close enough that you can access WiFi.
Where were you born?
Tell us a bit about yourself.
After WW2 ended my father ended his naval career in the
dockyards of Victoria. He got off the ship during the winter
months and didn’t want to return to Saskatchewan to shovel
snow, so he stayed. I was born in Victoria and although I have
done a considerable amount of travelling, I think he made the
right call and I have never wanted to live anywhere else.
I am currently in my fourth year at the University of Victoria.
I am studying geography and environmental studies. I have
always loved spending time outdoors and hope to dedicate my
career to ensuring that we will always have outdoor spaces
to enjoy. Besides volunteering I love to spend my spare time
kayaking, hiking, and reading.
My wife Eva and I have two perfect sons. They both agree with
their grandfather and live here. We have enjoyed camping and
hiking at many parks across Canada. Naturally when I retire I
plan to visit more of our national parks. Don’t get me wrong,
sometimes I go to Vegas.
What is your favourite park?
My favorite Regional Park is East Sooke. I love the endless
coastline and trails in the park. It is a great place to explore!
CRD Volunteers in Parks Spring 2014 Newsletter
Tell us a bit about yourself.
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Volunteer & Park Updates
New Volunteers Welcomed
On Feb. 20, nine new Park Stewards were added to our
volunteer team. Below is a list of the new Park Stewards and
their assigned parks.
•
Eric Addleman – Mt. Wells
•
Chantelle Clark – Elk/Beaver Lake
•
Alison Harle – East Sooke
•
Steven Leclerc- Island View Beach
•
Jeni Luther – Matheson Lake
•
Dylan Sayer – Island View Beach
•
Julie Thomson – Bear Hill
•
Lara Wear – Bear Hill
•
Eldred Williams – Mill Hill
2013 Park Visitation Statistics
Regional Parks actively monitors visitation levels throughout
the regional parks system. 57 counters are placed in strategic
locations to capture visitation data. This data assists Regional
Parks in developing park management plans and operational
strategies, including the identification of facility development
needs. When compared to 2012, visitation increased by 6.6%
or 382,947.
Regional Park / Trail
Albert Head Lagoon
2013 Visits
57,977
Brooks Point
5,822
Coles Bay
27,922
East Sooke
135,878
Devonian
50,301
Elk/Beaver Lake
1,484,164
Galloping Goose Regional Trail
1,825,947
Francis/King
93,807
Gonzales Hill
40,515
Horth Hill
63,906
Island View Beach
335,160
Jordan River (Sandcut Beach)
11,767
Lochside Regional Trail
1,099,396
Lone Tree Hill
5,729
Matheson Lake
49,784
Mill Hill
34,727
Mount Parke
5,430
Mount Wells
30,837
Mount Work
154,036
Sooke Potholes
104,178
Witty’s Lagoon
85,123
Sea to Sea (Harbourview)
31,106
Thetis Lake
Total
Volunteer Naturalist and Volunteer
Trail Ambassador Recruitment
Starting in April, we will be recruiting for year-round Volunteer
Naturalists at the Nature Centres at Francis/King and Witty’s
Lagoon regional parks and Summer Volunteer Naturalists at
Elk/Beaver Lake and Witty’s Lagoon regional parks. As well,
we will be recruiting more Volunteer Trail Ambassadors.
Please pass this information on to any folks who you think
might be interested and direct them to Colleen Long: clong@
crd.bc.ca, 250.360.3329 or crd.bc.ca/parks further details.
CRD Volunteers in Parks Spring 2014 Newsletter
429,934
6,163,446
Witty’s Lagoon Trail Closure
The trail and staircase at Witty’s Lagoon Regional Park, which
leads to the main beach off Witty Beach Road, is closed for
public safety. The clay hillside on which the stairs are built
is prone to slumping, causing slope instability. The bank’s
instability results from natural processes that feed the spit,
beach and intertidal features. As a result of a February 2014
engineering report, closure of the stairs was recommended.
Visitors can still access the beach from the main parking lot
off Metchosin Road. The beach is also accessible from Tower
Point during low tide.
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